Cardiopulmonary resuscitation (CPR): What you need to know

If someone is unconscious and not breathing normally, it’s very important to perform cardiopulmonary resuscitation (CPR) immediately. Doing so can save lives, for instance after a heart attack. In hospitals or doctors’ practices, medically trained staff can help fast in emergencies. Everywhere else, immediate first aid by other people is vital.

Then the main thing to do is stay calm and do the following:


Check whether the person is conscious and breathing normally.


If they aren’t, call the emergency services (112 in Germany and many other countries, 911 in the U.S.).


Start doing chest compressions.

If you follow these three steps right away, you can’t go wrong. The most important thing is to start helping immediately! Don’t hesitate for fear of doing something wrong. Good to know: If you’re not trained in CPR, you don’t need to give rescue breaths. In this article we will only describe how to do CPR without rescue breaths (hands-only CPR).

If you have access to an automated external defibrillator (AED) and someone else is there to help, you can resuscitate the patient using that too. But make sure that you only stop performing chest compressions when the defibrillator device tells you to stop.

How can you check whether someone is unconscious?

Speak to them in a loud, clear voice (for instance: “Hello?! Can you hear me?!”) and gently but firmly shake their shoulders. If the person doesn’t respond, they are probably unconscious.

How can you tell whether someone is no longer breathing normally?

Turn the unconscious person onto their back. Place one of your hands under their chin and gently push their head back, to open their airway. Look at their chest to see whether it is rising and falling. Put your ear close to their mouth and nose, and see whether you can hear them breathing or feel their breath against your ear. If you can’t hear or feel their breath, and if their chest isn’t moving, then they aren’t breathing.

In the first few minutes after a person’s heart has stopped beating, they may still breathe a bit – but not in a normal way. Instead, their breathing may be

  • irregular,
  • very slow,
  • very deep, or
  • accompanied by a noise that sounds like snoring.

Whatever you do, don’t wait until the person has stopped breathing altogether. If, after 10 seconds, you still aren’t sure whether the unconscious person is breathing normally, you should call the emergency services and start CPR.

Illustration: CPR – The first steps: a) Check consciousness, b) Check breathing, c) Dial 112 (or 911 in the U.S.)

What to remember when calling the emergency services

If someone else is with you and can help, ask them to call for an ambulance. Then you can immediately begin CPR.

If you are alone, dial 112 (or 911 in the U.S.) yourself. The emergency number 112 can be used free of charge throughout Europe, and can also be used in many countries outside of Europe. The person who answers the phone will ask you the following questions. Answer all of the questions as calmly and accurately as you can:

  • Who is calling?
  • What happened?
  • Where did it happen?
  • How many people are involved?

Do not hang up. Wait to see whether they ask any other questions or give you instructions. If your landline phone is within hearing distance, you have a cordless landline phone or are using a mobile phone, you can use the loudspeaker (“hands-free”) function and stay on the phone with the emergency services. The trained staff there can provide instructions and support over the phone.

How do you do chest compressions?

Kneel down next to the unconscious person. Place one hand on the center of their chest, with the heel of the hand on the lower half of the breastbone. Place your other hand on top, lacing your fingers together, and keeping your arms straight. Make sure that your hands don’t accidentally move to the side of the breastbone (towards the ribs) or that you don’t place them too low down (e.g. on the tip of the breastbone or on the belly).

Now push down on the person’s chest by moving your upper body downwards, keeping your arms straight. Then move your upper body back up, allowing the chest to rise again. Every time you do a chest compression, push the chest down by 5 to 6 cm (about 2 inches). Repeat the compressions at a fast rate of about two compressions per second (100 to 120 compressions per minute). Make sure that your arms remain stretched (don’t bend at the elbows), or they will soon get tired.

Illustration: Chest compressions – as described in the article

The same is true if a child is unconscious and no longer breathing normally: Start helping immediately! Doing chest compressions in the same way as you would with an adult is better than doing nothing. To find out how to do CPR on children, visit the website of the American Red Cross.

Doing chest compressions is exhausting. It is therefore a good idea to take it in turns with someone else if possible, switching every two minutes.

How long should you keep going for?

The CPR can be stopped if

  • the ambulance arrives and trained medical staff take over, or
  • the person who you are helping shows signs of consciousness or starts breathing normally again. If they stay unconscious despite breathing normally, put them in the recovery position.

If you’re too exhausted to carry on doing chest compressions, that’s an acceptable reason to stop as well.

Illustration: Recovery position

Deutsches Rotes Kreuz (DRK). Verhalten in Notfallsitutionen: Notruf 112.

Kragholm K, Wissenberg M, Mortensen RN et al. Bystander Efforts and 1-Year Outcomes in Out-of-Hospital Cardiac Arrest. N Engl J Med 2017; 376(18): 1737-1747.

Olasveengen TM, Semeraro F, Ristagno G et al. Basismaßnahmen zur Wiederbelebung Erwachsener (Basic Life Support). Leitlinien des European Resuscitation Council 2021. Notf Rett Med 2021 [Epub ahead of print]: 1-20.

Perkins GD, Handley AJ, Koster RW et al. European Resuscitation Council Guidelines for Resuscitation 2015: Section 2. Adult basic life support and automated external defibrillation. Resuscitation 2015; 95: 81-99.

IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Updated on February 21, 2022

Next planned update: 2025


Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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